This invention relates to a connector including a large number of leaf contacts arranged in an insulator.
A conventional connector 1 of the type described includes a plurality of leaf contacts 2 and an insulator 3 for holding the contacts 2, as illustrated in FIG. 1.
Referring to FIG. 2, each of the contacts 2 has a fixed portion 20 fixed to the insulator 3, an elastic spring portion 21 integrally connected to one end of the fixed portion 20, and a contact portion 22 integrally connected to one end of the elastic spring portion 21. As shown in FIG. 3, the elastic spring portion 21 is bent at its other end adjacent to the fixed portion 20, the bend being inwardly in a thickness direction of the contact 2. The contact portion 22 is bent at its intermediate portion in reverse to the elastic spring portion 21, namely, outwardly in the thickness direction of the contact 2. Since the contact 2 is bent in such a manner, the contact portion 22 of the contact 2 is brought into contact with a mating contact of a mating connector inserted into the insulator 3. At this time, an urging force of the elastic spring portion 21 is applied to the contact portion 22. Accordingly, the contact portion 22 is pressed against the mating contact of the mating connector. Since the elastic spring portion 21 and the contact portion 22 are bent as described above, the elastic spring portion 21 and the contact portion 22 protrude inwardly or one offset from one surface of the fixed portion 20 (the surface opposite to the mating contact of the mating connector inserted into the insulator 3).
In the conventional connector 1, the width of the fixed portion 22 is wider than that of the elastic spring portion 21 as illustrated in FIG. 2. The width of the contact portion 22 is equal to that of the elastic spring portion 21.
On assembling the connector 1, the contact 2 is inserted into the insulator 3 from a backside of the insulator 3 and is finally held in the insulator 3. As described above, the elastic spring portion 21 and the contact portion 22 protrude or are offset from one surface of the fixed portion 20. Accordingly, the insulator 3 requires a space for passing the elastic spring portion 21 and the contact portion 22 of the contact 2 in order to insert the contact 2 to a predetermined position within the insulator 3.
In this connection, the insulator 3 has a passage hole 30. The width d' of the passage hole 30 is slightly larger than the widths of the elastic spring portion 21 and the contact portion 22 of the contact 2. The insulator 3 also requires a space for holding the fixed portion 20 of the contact 2. In this connection, the insulator 3 is provided with a holding hole 31. The holding hole 31 is contiguous to the passage hole 30 in the thickness direction of the contact 2 held in the holding hole 31. The width e' of the holding hole 31 is slightly smaller than that of the fixed portion 20 of the contact 2.
Thus, the fixed portion 20 of the contact 2 is pressedly inserted into the holding hole 31 of the insulator 3 and held in the holding hole 31. As illustrated in FIG. 4, the width e' of the holding hole 31 is substantially wider than the width d' of the passage hole 30. With this structure, a pair of stepped surfaces 34 are formed between the holding hole 31 and the passage hole 30. These stepped surfaces 34 engage both side edges of the fixed portion 20 of the contact (2). By means of such an engagement, the contact 2 is located at a proper position in its thickness direction. The sum of the widths of these stepped surfaces 34 (hereinafter simply called the width of the stepped surfaces, is substantially equal to a difference between the width b of the elastic spring portion 21 and the width c' of the contact portion 22.
In the connector of the type described, it is a recent demand to achieve a high-density arrangement of contacts, namely, to arrange a large number of contacts in an insulator at a reduced arrangement pitch.
It is noted that the arrangement pitch of the contacts must be greater than the width of the fixed portion of each contact. Now, consideration will be made as regards two approaches to reduce the arrangement pitch of the contacts. One approach is to reduce the width of the fixed portion of the contact alone. Another approach is to reduce an entire width of the contact.
Practically, it is impossible to adopt the former approach of reducing the width of the fixed portion alone. It is noted that the width of the stepped surfaces is substantially equal to the difference between the width of the fixed portion and the widths of the elastic spring portion and the contact portion as described above. If the width of the fixed portion alone is reduced while the widths of the elastic spring portion and the contact portion are kept unchanged, the width of the stepped surfaces is reduced accordingly. As a result, engagement between the contact and the stepped surfaces becomes unreliable. Thus, when the width of the fixed portion alone is reduced, the contact is unfavorably displaced from a normal portion within the insulator. Accordingly, it is impossible in the conventional connector to reduce the width of the fixed portion of the contact alone.
On the other hand, the latter approach of reducing the entire width of the contact assures the sufficient width of the stepped surfaces. Accordingly, the contact is not displaced from the normal position within the insulator. However, this approach is not practical. If the entire width of the contact is reduced, the width of the elastic spring portion is reduced. The elastic spring portion having such a reduced width can not exert a sufficient urging force against the contact portion. As a result, the contact portion can not be brought into a tight contact with the mating contact of the mating connector.
As described, it is difficult to achieve a high-density arrangement of the contacts in the conventional connector of the type described.